Two-color above threshold ionization of helium and xenon has been used to analyze the synchronization between individual pulses of the femtosecond extreme ultraviolet (XUV) free electron laser in Hamburg and an independent intense $120\mathrm{fs}$ mode-locked Ti:sapphire laser. Characteristic sidebands appear in the photoelectron spectra when the two pulses overlap spatially and temporally. The cross-correlation curve points to a $250\mathrm{fs}$ rms jitter between the two sources at the experiment. A more precise determination of the temporal fluctuation between the XUV and infrared pulses is obtained through the analysis of the single-shot sideband intensities.

In this Letter we report on a near collective x-ray scattering experiment on shock-compressed targets. A highly coupled Al plasma was generated and probed by spectrally resolving an x-ray source forward scattered by the sample. A significant reduction in the intensity of the elastic scatter was observed, which we attribute to the formation of an incipient long-range order. This speculation is confirmed by x-ray scattering calculations accounting for both electron degeneracy and strong coupling effects. Measurements from rear side visible diagnostics are consistent with the plasma parameters inferred from x-ray scattering data. These results give the experimental evidence of the strongly coupled ionic dynamics in dense plasmas.

Information Communication Technologies are increasingly present in the African educational system at all educational levels. However, their integration into pedagogical practices to improve the qua...

The temporal evolution of the opacity of an iron plasma at high temperature (30–350 eV) and high density ($0.001–0.2\mathrm{g}{\mathrm{cm}}^{-3}$) has been measured using a nickel-like silver x-ray laser at 13.9 nm. The hot dense iron plasma was created in a thin (50 nm) iron layer buried 80 nm below the surface in a plastic target that was heated using a separate 80 ps pulse of 6–9 J, focused to a $100\mu \mathrm{m}$ diameter spot. The experimental opacities are compared with opacities evaluated from plasma conditions predicted using a fluid and atomic physics code.